JPH08183835A - Thermosetting resin composition, adhesive sheet, and adhesive-backed metal foil - Google Patents

Abstract

PURPOSE: To obtain a thermosetting resin composition which becomes flowable upon heating, is excellent in heat resistance and adhesion, and is usable for bonding at 180 deg.C or below; and to obtain an adhesive sheet and an adhesive- backed metal foil which are applications of the composition as an adhesive. CONSTITUTION: The composition comprises a linear epoxy polymer obtained by polymerizing a bifunctional epoxy resin with a bifunctional phenol in an equivalent ratio of the epoxy group to the phenolic hydroxyl group of 1/(0.9-1.1), a resin having dihydrobenzoxazine rings, and a polyfunctional epoxy resin.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a printed circuit board, TAB,
The present invention relates to a thermosetting resin composition which can be used for a composite lead frame, a laminated material and the like and has excellent heat resistance and which can be adhesively cured at a low temperature, an adhesive sheet using the same, and a metal foil with an adhesive.

[0002]

2. Description of the Related Art Among insulating adhesives for electronic materials, an epoxy resin composition is an epoxy resin composition containing a high molecular weight epoxy polymer capable of forming a film, a polyfunctional epoxy resin and a curing agent. Known (Japanese Patent Laid-Open No. 5-
25368). Also, the adhesive can be cured at low temperature,
As a heat-resistant polyimide resin composition, one composed of polyimide, polymaleimide and epoxy resin is known (see Japanese Patent Laid-Open No. 5-339344).

[0003]

However, since this epoxy resin composition has low heat resistance, it is not suitable for use in the field of electronic components such as COB (chip on board) substrates and BGA (ball grid array) substrates. There is a drawback that the elastic modulus of the object at a high temperature cannot be maintained, and defective wire bonding at the time of chip mounting cannot be avoided. on the other hand,
The polyimide resin composition is useful for bonding between planes because it does not melt and flow even when heated, but the fluidity of the adhesive is high because it fills the recesses between the circuits, as in multi-layered bonding in the manufacture of multilayer printed boards. Cannot be applied to applications that require.

The present invention is a thermosetting resin composition which has fluidity when heated, is excellent in heat resistance and adhesiveness, and can be adhered at a low temperature of 180 ° C. or less, and an adhesive for the thermosetting resin composition. The present invention provides an adhesive sheet and a metal foil with an adhesive, which are applied products as the above.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that by blending a specific linear epoxy polymer with a resin having a dihydrobenzoxazine ring and a polyfunctional epoxy resin, The inventors have found that the above problems can be solved, and have completed the present invention based on this finding. That is, in the present invention, a bifunctional epoxy resin and a bifunctional phenol are mixed with an epoxy group / phenol hydroxyl group = 1 /
Provided is a thermosetting resin composition in which a resin having a dihydrobenzoxazine ring and a polyfunctional epoxy resin are mixed with a linear epoxy polymer obtained by polymerizing at an equivalent ratio of (0.9 to 1.1). It is a thing.

The linear epoxy polymer used in the present invention is
The bifunctional epoxy resin and the bifunctional phenols are mixed with each other, and the compounding equivalent ratio of the bifunctional epoxy resin and the bifunctional phenols is epoxy group / phenolic hydroxyl group = 1 / (0.9 to 1.1),
In the presence of a catalyst, in an amide solvent having a boiling point of 130 ° C. or higher,
It is obtained by heating and polymerizing at a reaction solid content concentration of 5 to 50% by weight.

The bifunctional epoxy resin may be any compound as long as it is a compound having two epoxy groups in the molecule, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, Alicyclic epoxy resin, aliphatic chain epoxy resin, diglycidyl ether of bifunctional phenols,
There are diglycidyl ether compounds of difunctional alcohols, halides thereof, hydrogenated products thereof, and the like. There is no limitation on the molecular weight of these compounds. Moreover, several kinds of these compounds can be used together. Components other than the bifunctional epoxy resin may be included as impurities.

The bifunctional phenol may be any compound as long as it has two phenolic hydroxyl groups, and examples thereof include monocyclic bifunctional phenols such as hydroquinone, resorcinol, catechol, and polycyclic bifunctional phenols. Examples include bisphenol A, bisphenol F, their halides, and alkyl-substituted compounds. There is no limitation on the molecular weight of these compounds. Similar to the bifunctional epoxy resin, several kinds of these compounds can be used together. Further, a component other than the bifunctional phenol may be contained as an impurity.

The catalyst for polymerizing the bifunctional epoxy resin and the bifunctional phenol may be any compound having a catalytic function for promoting the etherification reaction of the epoxy group and the phenolic hydroxyl group. Examples thereof include alkali metal compounds, alkaline earth metal compounds, imidazoles, organic phosphorus compounds, secondary amines, tertiary amines, and quaternary ammonium salts. Examples of alkali metal compounds include hydroxides, halides, organic acid salts, alcoholates, phenolates, hydrides, borohydrides and amides of sodium, lithium or potassium. These catalysts can be used in combination.

The amide-based solvent may be any as long as it can dissolve the bifunctional epoxy resin and the bifunctional phenols used as raw materials, and examples thereof include formamide, N-methylformamide,
N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide,
Examples include N, N, N ', N'-tetramethylurea, 2-pyrrolidone, N-methylpyrrolidone, and carbamic acid ester. These solvents can be used in combination. Further, it may be used in combination with another solvent represented by a ketone solvent or an ether solvent.

The compounding equivalent ratio of the bifunctional epoxy resin and the bifunctional phenols is epoxy group / phenolic hydroxyl group = 1.
/(0.9-1.1). If the equivalent of the phenolic hydroxyl group is less than 0.9 equivalent, the polymer does not linearly polymerize,
Side reactions occur and crosslink, making the resin insoluble in the solvent. If the equivalent of the phenolic hydroxyl group is larger than 1.1 equivalents, the polymerization of the resin will not proceed.

The amount of the catalyst to be blended is not particularly limited, but in general, the amount of the catalyst is 0.001 relative to 1 mol of the bifunctional epoxy resin.
It is about 01 to 0.2 mol. When the amount of the catalyst compounded is less than 0.0001 mol with respect to 1 mol of the bifunctional epoxy resin, the high molecular weight reaction is remarkably slow, and when it is more than 0.2 mol, side reactions increase and the linear molecular weight is increased. It may not be turned into.

The solid content concentration in the polymerization reaction using an amide solvent may be 50% (wt%, the same applies hereinafter) or less, but preferably 10 to 30%. As the concentration becomes higher, side reactions increase, and it becomes difficult to form a linear polymer having a high molecular weight. When the concentration is lower than 10%, the reaction is slow and it is difficult to increase the molecular weight. Therefore, when the polymerization reaction is carried out at a relatively high concentration and a linear high molecular weight epoxy polymer is to be obtained, the reaction temperature may be lowered and the catalyst amount may be reduced. The molecular weight of the high molecular weight epoxy polymer is
There is no problem as long as the resin alone has a film-forming ability and a molecular weight capable of obtaining a sheet-shaped adhesive. Such a molecular weight is approximately 70,000 or more. More preferably, 1
It is from 0,000 to 150,000. The upper limit of the molecular weight of the high molecular weight epoxy polymer is not particularly limited.
However, in reality, when the molecular weight is 150,000 or more, it is difficult to accurately measure the molecular weight and the viscosity becomes high, so that it becomes difficult to handle as a varnish.

The resin having a dihydrobenzoxazine ring to be blended with the high molecular weight epoxy polymer is 70 to 110 by adding a mixture of a compound having a phenolic hydroxyl group and a primary amine to an aldehyde heated to 70 ° C. or higher.
C., preferably 90 to 100.degree. C. for 20 to 120 minutes, and then dried under reduced pressure at a temperature of 120.degree.

The compound having a phenolic hydroxyl group is a phenol novolac resin, a resole resin, a phenol-modified xylene resin, an alkylphenol resin, a melamine phenol resin, a polybutadiene-modified phenol resin, or another phenol resin, a bisphenol compound, a biphenol compound, a trisphenol compound, or a tetraphenol compound. Mention may be made of phenolic compounds. When a phenolic resin is used, the resin having a dihydrobenzoxazine ring has a structural unit A represented by the following formula (A) and a structural unit B represented by the following formula (B). When the molar ratio (A / B) of the structural unit B is 1 / (0.25 to 29) and each structural unit is a resin bonded directly or through an organic group, strength and heat resistance A cured product excellent in that point can be obtained.

Embedded image (However, R ¹ is a methyl group, a cyclohexyl group, a phenyl group or a substituted phenyl group, and hydrogen of the aromatic ring of the structural unit A and the structural unit B excludes one of the ortho positions of the hydroxyl group of the structural unit A. , May be substituted with any substituent.)

Specific examples of primary amines include substituted anilines such as methylamine, cyclohexylamine, aniline, toluidine and xylidine. When an aliphatic amine is used, the resulting resin cures quickly, but the heat resistance of the cured product is somewhat inferior. When an aromatic amine such as aniline is used, the heat resistance of the cured product is good, but the curability is slow.

Examples of the polyfunctional epoxy resin blended with the high molecular weight epoxy polymer include the following epoxy compounds having an average of two or more epoxy groups per molecule. Bisphenol epoxy resin, halogenated bisphenol epoxy resin, bisphenol novolac epoxy resin, halogenated bisphenol novolac epoxy resin, phenol novolac epoxy resin, halogenated phenol novolac epoxy resin,
Alkylphenol novolac epoxy resin, polyphenol epoxy resin, polyglycol epoxy resin, cycloaliphatic epoxy resin. These may be used alone or in combination of two or more.

The blending ratio of the high molecular weight epoxy polymer, the resin having a dihydrobenzoxazine ring and the polyfunctional epoxy resin in the present invention is 4 for the high molecular weight epoxy polymer.
It is preferably from 0 to 70% by weight. When the amount of the high molecular weight epoxy polymer is less than 40% by weight, the resin composition becomes brittle and the handling becomes difficult. When it exceeds 70% by weight, the fluidity of the adhesive is insufficient and the embedding of the unevenness becomes insufficient in the application where the unevenness is filled while adhering, such as the multilayer adhesion in the multilayer printed board structure. Further, it is preferable that a resin having a dihydrobenzoxazine ring and a polyfunctional epoxy resin are used in combination, and each is blended in an amount of 15% by weight or more. If a resin containing a dihydrobenzoxazine ring is not blended, the glass transition temperature and softening temperature of the resin composition after heat curing are lowered, and the elastic modulus at high temperature cannot be maintained. This is because the adhesiveness is poor unless a polyfunctional epoxy resin is blended.

The resin composition of the present invention is preferably molded in advance into a sheet of 0.01 to 0.1 mm,
It is convenient to use it as a sheet adhesive. Further, the resin composition of the present invention is impregnated into a glass cloth, a glass mat, an aromatic polyamide fiber cloth, an aromatic polyamide fiber mat or the like as a varnish, and the resin is semi-cured to be used as a fiber-reinforced sheet adhesive. You can also

The resin composition of the present invention may be used as a varnish, applied as it is to a dressing product, dried, and then heated and pressed to bond to another dressing product. In this case, it is preferable to heat and press at a temperature of 100 to 250 ° C. and a pressure of 0.1 to 10 MPa for 20 minutes or more. In particular, the temperature is 150 to 200 ° C, the pressure is 1 to 4 MPa.
It is more preferable to heat and press for 60 to 120 minutes.

The resin composition of the present invention is used as a varnish, and the adhesive-coated metal foil obtained by applying the varnish to one side of a metal foil and drying the varnish is IVH (Interstitial Via).
It is particularly useful for manufacturing a multilayer circuit board having a hole).

[0022]

【Example】

Example 1 (Synthesis of High Molecular Weight Epoxy Polymer) 177.5 g of bisphenol A type epoxy resin (epoxy equivalent: 177.5) as a bifunctional epoxy resin, bisphenol A as a bifunctional phenol (hydroxyl equivalent: 115.5) 11
5.5 g, sodium hydroxide as an etherification catalyst 1.
77 g was dissolved in 547.9 g of N, N-dimethylformamide which is an amide solvent, and the solid content concentration in the reaction system was 30% by weight. While stirring this mechanically,
The temperature in the reaction system was kept at 120 ° C. in an oil bath of 5 ° C., and the mixture was stirred as it was for 4 hours. As a result, the viscosity is 12,
It was saturated at 800 mPa · s, and the reaction was completed. The weight average molecular weight of the obtained high molecular weight epoxy polymer was 72, as measured by gel permeation chromatography.
500, 59,20 as measured by the light scattering method
It was 0. The reduced viscosity of the dilute solution of the high molecular weight epoxy resin was 0.770 dl / g.

(Synthesis of Resin Having Dihydrobenzoxazine Ring) 170 g of phenol novolac resin (corresponding to 1.6 mol of hydroxyl group) was added with 93 g of aniline (1 mo)
l) and mixed at 80 ° C. for 5 hours to prepare a uniform mixed solution. Formalin 162 in a 1 liter flask
g was charged, the mixture was heated to 90 ° C., and the novolac / aniline mixture was added little by little over 30 minutes. After addition is complete, 3
The reaction was completed by keeping at the reflux temperature for 0 minutes. Furthermore, 10
Condensed water was removed by reducing the pressure to 7 kPa or less at 0 ° C. for 2 hours to obtain a thermosetting resin in which 71% of reactive hydroxyl groups were dihydrobenzoxazinized.

The resulting high molecular weight epoxy polymer solution (3
40 g of a resin having a dihydrobenzoxazine ring and 40 g of a bisphenol A type epoxy resin (epoxy equivalent 177.5) were dissolved in 400 g of a 0 wt% solution) to form a varnish.

The resulting varnish was cast on a glass plate and 1
After drying at 00 ° C for 10 minutes, peel it from the glass plate, fix it on an iron frame, and dry at 140 ° C for 15 minutes, thickness 50μ.
m sheets were obtained.

An inner layer circuit is formed on both sides of a glass-based epoxy double-sided copper-clad laminate (thickness: 0.2 mm, copper foil: 18 μm), and the adhesive sheet obtained above and a thickness of 3 are formed on both sides thereof.
A 5 μm copper foil was placed, and heated and pressed at 180 ° C. and 3 MPa for 90 minutes to obtain a four-layer shield plate.

Example 2 The varnish obtained in Example 1 was applied to the roughened surface of a copper foil having a thickness of 35 μm and heated at 100 ° C. for 10 minutes and then at 140 ° C. for 15 minutes to obtain an adhesive having a thickness of 50 μm. Layers were applied to obtain a copper foil adhesive sheet. Using the obtained adhesive sheet with copper foil instead of the adhesive sheet and copper foil of Example 1, a four-layer shield plate was produced by heating and pressing under the same conditions as in Example 1.

Comparative Example 1 The high molecular weight epoxy polymer solution (30
(Wt% solution) 400 g and bisphenol A type epoxy resin (epoxy equivalent 177.5) 80 g, dicyandiamide 4.73 g, 2-ethyl-4-methylimidazole 0.45 g, N, N-dimethylformamide 10 g, and varnish. Then, an adhesive sheet was obtained in the same manner as in the example. Using the obtained adhesive sheet, a four-layer shield plate was obtained in the same manner as in Example 1.

Comparative Example 2 Using the varnish obtained in Comparative Example 1, an adhesive sheet with copper flakes was obtained under the same conditions as in Example 2. A four-layer shield plate was obtained by using the obtained adhesive sheet with copper flakes and heating and pressing under the same conditions as in Example 2.

Comparative Example 3 A four-layer shield plate was obtained by using a commercially available polyimide adhesive sheet and heating and pressing under the same structure and conditions as in Example 1.

With respect to the four-layer shield plates obtained in each of the above Examples and Comparative Examples, the outer layer copper foil was etched to fill the inner layer circuit with resin, and the outer layer copper peeling strength (kN /
m) and the change in appearance after floating in a solder bath at 288 ° C. for 30 seconds.

[0032]

[Table 1]

[0033]

EFFECTS OF THE INVENTION The thermosetting resin composition of the present invention has excellent heat resistance and adhesiveness, can be adhered at a low temperature, and can be processed into a sheet in advance. Furthermore, since it is soluble in a solvent, it can be applied to the carrier in advance and adhered to another carrier. Unlike the conventional sheet-like adhesive, the sheet-like adhesive of the present invention has fluidity of the adhesive and thus can be suitably used for adhesion of the inner layer circuit of the multilayer printed wiring board. Further, the metal foil with adhesive of the present invention,
Since IVH can be easily produced by making a hole in advance with a drill or the like and then performing multilayer adhesion,
It is preferably used for manufacturing a multi-layer circuit board having H.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location C09J 7/02 JHX JKA 163/00 JFP (72) Inventor Masafumi Tanaka 1500 Ogawa, Ogawa, Shimodate-shi, Ibaraki Prefecture Hitachi Chemical Co., Ltd. in Shimodate Factory (72) Inventor Teruki Aizawa 1500 Ogawa, Shimodate, Ibaraki Prefecture Hitachi Chemical Co., Ltd. in Shimodate Factory (72) Yasuyuki Hirai 1500 Ogawa, Shimodate, Ibaraki Hitachi Chemical Co., Ltd. Company Shimodate Factory

Claims (5)

[Claims] 1. An epoxy group / phenolic hydroxyl group = 1 / (0.9 to 0.9) containing a bifunctional epoxy resin and a bifunctional phenol.
A thermosetting resin composition in which a resin having a dihydrobenzoxazine ring and a polyfunctional epoxy resin are blended with a linear epoxy polymer obtained by polymerization at an equivalent ratio of 1.1). 2. The linear epoxy polymer has a molecular weight of 70,
The thermosetting resin composition according to claim 1, which is 000 or more. 3. A thermosetting resin having a dihydrobenzoxazine ring has a structural unit A represented by the following formula (A) and a structural unit B represented by the following formula (B). The molar ratio (A / B) of the unit B is 1 / (0.25-2
The thermosetting resin composition according to claim 1, which is 9) and is a resin in which each structural unit is bonded directly or via an organic group. Embedded image (However, R ¹ is a methyl group, a cyclohexyl group, a phenyl group or a substituted phenyl group, and hydrogen of the aromatic ring of the structural unit A and the structural unit B excludes one of the ortho positions of the hydroxyl group of the structural unit A. , May be substituted with any substituent.) 4. An adhesive sheet in which the thermosetting resin composition according to claim 1 is formed into a sheet. 5. A metal foil with an adhesive, wherein an adhesive layer made of the thermosetting resin composition according to claim 1 is provided on one surface of the metal foil.